This is where teemo shines as a laner. Your damage level 1 is really high with your poison dart buffed auto attacks. on top of this, your Q provides a fairly strong nuke, and a blind that makes you nearly impossible to fight against. Don't be afraid to push the lane as teemo, because you have an infinite supply of wards at your disposal. Harass enemies whenever they go in for a last hit with an auto attack and blinding dart, this not only hits them for a good chunk of damage, it also may prevent them from getting the last hit due to the blind making their attack miss. Keep this harassment up, and then once their at bout half, go in for the kill with ignite, flash, move quick, and your regular damage output.

Teemo has a weird mid game. He isn't that great at ganking, so unlike many champions, when you shove the lane, you keep shoving til you can kill either your opponent or the tower. Because of teemo's mobility, you can typically chase enemies with no hope of them escaping. Keep in mind however, to try and avoid ANY damage, because this will make your W's passive go away and making chasing near impossible while its on cooldown. Plant mushrooms liberally around your lane and any heavily trafficked areas.

Teemo's late game is weird. He isn't much of a team fighter, because he's really easy to focus down. Because of this, play as if you're an ADC. Do NOT focus their squishies, unless it is safe to do so, and doesnt make you compromise your position for the rest of the fight. Plant minefields. Minefields are one of AP teemo's strong points, Pick a point you don't want your enemies getting past, and shroom the **** out of it. If your team can, try to bait the enemy team into running through it allowing for easy kills with little risk. Overall, teemo is a very mediocre champion. You'll carry some games, but most of the time he suffers from lack of a late game and his team loses, because of this, you should try to win before the 30 minute mark or so.